Siliceous molecular sieves or zeolites wherein certain of the silicon atoms in the crystalline framework have been replaced by titanium atoms are well-known in the art and have been extensively investigated as active and selective oxidation catalysts. For example, U.S. Pat. No. 4,401,501 describes the synthesis of "TS-1" titanium silicalite having a framework structure isomorphous with ZSM-5 (i.e., an MFI topology). Titanium silicalite catalyzes the epoxidation of olefins with hydrogen peroxide, as described in U.S. Pat. No. 4,833,260. In an effort to modify or improve the properties of such materials, the incorporation of additional metal atoms into titanium-containing zeolites has also been attempted. For instance, EP 226,257 teaches a crystalline material of zeolitic character containing silicon, titanium and aluminum oxides. Similarly, EP 266,258 teaches a zeolite material containing silicon, titanium and iron oxides. Zeolites containing oxides of silicon, titanium and gallium are described in EP 266,825. However, there have apparently been no reports to date of a successful preparation of zeolites containing silicon and tellurium oxides or silicon, titanium and tellurium oxides. The catalytic properties of such materials are unknown.